of rotated component loadings for each TF point. Five components were retained, based upon inspection of the scree plot of singular values, representing the relative variance accounted for by each component, for a break, or elbow. In a final step, each participant’s average TF surface was weighted using the extracted TF-PCA components. To weight the original TF data, each time-frequency point is multiplied by the corresponding point in the matrix of rotated loadings for each component. This produces weighted data surfaces, for each participant for each TF-PCA component, whose data points represent energy in units weighted by the component loadings. For subsequent analyses, component scores representing the peak energy on the weighted TF-PCA surface were used.
